A plant 10 in a tree structure may include components which constitute various levels from a lower level to a higher level, and the uppermost level layer of the tree structure of the plant 10 can be selected as needed by a user.
For example, as shown in FIG. 1, a boiler (BOILER) and a turbine (TURBINE) may be disposed at the uppermost level layer (LEVEL 1). A lower level layer of the boiler may include a draft system (DRAF-SYS), a furnace system (FURNACE), a fuel system (FUEL & FIRING), and a desulfurization system (FGD & EP), etc. (LEVEL 2). And a lower level layer of the draft system (DRAF-SYS) may include a forced draft fan (FD FAN), an induced draft fan (ID FAN), a primary air fan (PA FAN), and GAH (LEVEL 3). The forced draft fan (FD FAN) may include a forced draft fan A (FD FAN-A) and a forced draft fan B (FD FAN-B) (LEVEL 4), and a lower level layer of the forced draft fan A (FD FAN-A) may include primary air fan pressure (FDFA-INOUT PR), forced draft fan temperature (FDFA-INOUT TEMP), forced draft fan air flow (FDFA-AIR FLOW), a forced draft fan bearing (FDFA-BRG&WIND), and forced draft fan vibration (FDFA-VIBRATION) (LEVEL 5). In addition, a lower level layer of the primary air fan pressure (FDFA-INOUT PR) may include SPECIFIC ENERGY #1 FD, FDF-A SUCTION-PRESSURE, FDF-A IN PRESS ABS, FDF-A IN PRESS ABS, FDF-A OUT PRESS, and FDF-A INNET PRESS.
Generally, to measure a health index of the boiler (BOILER) which is disposed in the uppermost level layer, an actual measurement value of the lowermost level component is measured and then the health index of the next upper level layer is calculated without correction of the actual measurement value of the lowermost level component. This process is repeated to calculate the health index of the uppermost level layer.
According to this method, however, even when an actual measurement value of a critical component of the lowermost level layer or the upper level layer deviates from a normal range, the health index of the uppermost level layer is calculated as in a normal state, because their severity or importance becomes lowered while the actual measurement value of the critical component is transmitted to the upper level layer. In other words, the conventional health index calculation method is less reliable because of distortion of the health index.
And the distorted index may result in missing the timing for repairing, inspecting and replacing the components having abnormal value, and as a consequence, the entire plant may be shut down (trip), which may lead to a serious damage.
In order to prevent the plant from the occurrence of the above problem, it is required to monitor in real time whether actual measurement values of components of the lowermost level layer as well as the components of upper level layers constituting the plant are within the normal range.
In addition, in certain circumstances, even though some of actual measurement values of components of lower level layers momentarily deviate from the normal range, which does not affect the health index of the uppermost level layer, and vice versa.
Consequently, there has been a high necessity for developing a system and method for monitoring a health index of a plant only by checking a health index of the upper level layer without monitoring whether an actual measurement value of the lower level layer is within a normal range.